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Can't get realistic stone effect


Stewart Reid
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Hi there, :confused:

 

Can't get realistic stone effect

 

Can someone help? I am trying to get a really realistic stone effect using the attached texture "stone 44". I am basically just trying different bump map settings but can't seem to get a good result.

 

Stone 5 attached has the following settings - Diffuse tile 4.5 x 4.5, bump tile 4.5 x 4.5 and bump amount - 0.2 (uses stone 44 for diffuse and bump)

 

Stone 6 attached has the following settings - Diffuse tile 4.5 x 4.5, bump tile 4.5 x 4.5 and bump amount - 0.5 (uses stone 44 for diffuse and bump)

 

Stone 7 attached has the following settings - Diffuse tile 4.5 x 4.5, bump tile 4.5 x 4.5 and bump amount - 1.2 (uses stone 44 for diffuse and a mono version of stone 44 for bump)

 

I think Stone 7 is the best using the mono bump map but it's nothing like a stone effect I would like. I found a really amazing 3d stone image on the net I would love to imitate (attachment - cool stone).

 

Can anyone please point me in the right direction? I'm probably missing something fundamental.

 

Thank you in advance.

 

Kind Regards,

 

Stewart Reid

 

ps - I'm pretty new to all this so please forgive my ignorance.

Edited by Stewart Reid
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Thanks guys,

 

I downloaded 'crazy bump' and gave it a go. Wow, it's really amazing. One thing though, I'm still a bit lost as to setting up a decent realistic effect in max.

 

I used the stone 44 texture (attached to my opening post on this thread) on crazy bump and the effect looked great but the end result was that it produced new maps for me - diffuse, displacement, occlusion and spec. However, when I went to install these maps into my material editor I was back to square one.

 

Without being too cheeky can anyone give me some good, basic stone settings. This would be very much appreciated (max 9 m.ray).

 

Thank you

 

Stewart

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Stewart - open up the diffuse bitmap (the color one) in photoshop and make your own bump/displace map. Convert the image to greyscale - Anything white will protrude most, and black least. Add a layer and paint all the grout black, then select each brick and add a brightness/contrast layer to make them all different heights (shades of white).

 

Then add this bitmap to your bump and/or displace slot.

 

If youre adding this to the basic displace slot (the one 2 under the bump) you need to tasselate the object - otherwise use the mental ray connection displace further down the list.

 

Unlock it, add the height displacement map to the material slot and then add the bitmap to that and specify your heights.

 

Id offer to do you an example, but Im on Max2009.

Edited by Ky Lane
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I'm guessing here but what I think the issues are:

 

- Your stone isn't that great an image. Too small, too much.. something. Compression artefacting, oversharpened.. It isn't going to work well unless it renders a good bit smaller than the map itself appears at actual size on screen.

 

- Your stone is already strongly lit. It is its own realistic effect. A bump map could increase this effect, but in order to get a visible effect in the minor bumps you will totally blow out the already black and white bit and the whole thing will start to look crass. This is related to the next point.

 

- I think you are using the stone image itself as the source for the bump. There are two sub-problems from that.

 

- - It isn't accurate or correct for the surface you are trying to bump

- - It fights the highlighting already in the image

 

Imagine a sphere. Lit it will have a highlight at 10:30 o'clock, be medium in the middle and dark over towards 4:00. That's fine and just what a sphere should look like.

 

A bump map to indicate that sphere would be white in the dead center where it is nearest you and move towards black at all the outside edges.

 

The white part is nearest.

 

Now imagine using the image of the sphere as the bump map for it. The highlight at 10 is considered nearest so it gets shaded flat and out from there gets brightened up because it must be angling towards the light. The center is toned medium so it must be on the shady side of the bump so it gets darkened. The end result, the highlight gets weakened and spread, the neutral area gets darkened and merged into the shadow areas. Your low end gets darker, your upper end gets darker, your relief gets flattened. ... at best.

 

Now if you move the light to 3:00 and use the same diffuse map for diffuse and bump you get two highlights, more flattening....

 

I can't point at specific evidence that this is what is happening in your images, but the lead in makes me think it may.

 

You CAN use a contrasty real world image as a bump map. You will get a result. It will not be an echo, merely and interesting cousin, of the original geometry and it may even be passable for your needs.

 

Ideally you want your diffuse map to be only about color. A nice diffuse map for use with bump/normal/displacement will tend to look flat and uninspiring. It tells only "what color is the actual thing." I believe the pros like overcast days for their photography work to keep the modelling to a minimum and all the tonality nice and even. If something is dark that's because it's made of dark, not because it's in shadow. Then the minor shading variations and highlights attributable to the lighting from the variations in geometry come from the bump.

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Hi Ky,

 

Further to you advise in regard to the the stone mapping I am now using a slightly different texture. See 'Stone 22A' attached. I know it's not amazing but I'll use it for experimenting. See also 'Stone 22A black grout white stone B' for my contrast texture as you described (black grout and different white shades of stone done in photoshop).

 

I applied a bump map at a few different settings and have attached 2 of them. Please see attachment 'B' set at a bump value of 4 and 'C' set at a bump value of 0.5. I think 'C' at 0.5 is best but not amazing and I think the black and white texture maybe comes through too strong on 'B' - would that be right ?

 

Anyway regarding displacement I wasn't exactly sure what you meant by tasellating texture so I opted instead to go for the method of the m.ray connection but unfortunately nothing appeared to happen on render. Something I'm not doing right for sure.

 

Can you see where I'm going wrong?

 

Thanks also for the example of textures?

 

Stewart

 

ps - have just also read Peter's reply and I can also see what he means about my texture having shadow on it. I notice your bricks look very flat, I will have to maybe aim for an image like this.

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I'm guessing here but what I think the issues are:

 

- Your stone isn't that great an image. Too small, too much.. something. Compression artefacting, oversharpened.. It isn't going to work well unless it renders a good bit smaller than the map itself appears at actual size on screen.

 

- Your stone is already strongly lit. It is its own realistic effect. A bump map could increase this effect, but in order to get a visible effect in the minor bumps you will totally blow out the already black and white bit and the whole thing will start to look crass. This is related to the next point.

 

- I think you are using the stone image itself as the source for the bump. There are two sub-problems from that.

 

- - It isn't accurate or correct for the surface you are trying to bump

- - It fights the highlighting already in the image

 

Imagine a sphere. Lit it will have a highlight at 10:30 o'clock, be medium in the middle and dark over towards 4:00. That's fine and just what a sphere should look like.

 

A bump map to indicate that sphere would be white in the dead center where it is nearest you and move towards black at all the outside edges.

 

The white part is nearest.

 

Now imagine using the image of the sphere as the bump map for it. The highlight at 10 is considered nearest so it gets shaded flat and out from there gets brightened up because it must be angling towards the light. The center is toned medium so it must be on the shady side of the bump so it gets darkened. The end result, the highlight gets weakened and spread, the neutral area gets darkened and merged into the shadow areas. Your low end gets darker, your upper end gets darker, your relief gets flattened. ... at best.

 

Now if you move the light to 3:00 and use the same diffuse map for diffuse and bump you get two highlights, more flattening....

 

I can't point at specific evidence that this is what is happening in your images, but the lead in makes me think it may.

 

You CAN use a contrasty real world image as a bump map. You will get a result. It will not be an echo, merely and interesting cousin, of the original geometry and it may even be passable for your needs.

 

Ideally you want your diffuse map to be only about color. A nice diffuse map for use with bump/normal/displacement will tend to look flat and uninspiring. It tells only "what color is the actual thing." I believe the pros like overcast days for their photography work to keep the modelling to a minimum and all the tonality nice and even. If something is dark that's because it's made of dark, not because it's in shadow. Then the minor shading variations and highlights attributable to the lighting from the variations in geometry come from the bump.

 

Peter,

 

Thank you for this information. I am going through what you have written and am starting to really undertsand the methodology. Please see my reply, just posted, to Ky. For a start I will go and have a look for a flatter image.

 

Kind regards and Thanks

 

Stewart

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Hi Ky,

 

I followed through Jeff's tutorial on displacement and it definitely enlightened me however I'm not quite there yet. I think it looks not too bad close-up (please see 'close-up' attachment) but further away (please see my thread on the WIP forum) it's hard to see if there is any displacement there. It could maybe be the distance but I can't help thinking I could get it better from a distance and close up if I tweaked something.

 

I'm using the mantal ray texture method along with a DGS material. Please see the rest of my attachments for this info.

 

Any help would be hugely appreciated.

 

Thank you in advance.

 

Regards

 

Stewart

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